Related papers: Lepton Universality, Rare Decays and Split Fermion…
Though not completely a surprise according to the standard model and existing indirect constraints, the Higgs-like particle, h, of mass around 125 GeV recently observed at the LHC may offer an additional window to physics beyond the…
We discuss two dedicated observables in exclusive B -> K* l+ l- decay that can be used to study effects of physics beyond the standard model, namely the forward-backward asymmetry in the lepton spectrum and the isospin-asymmetry between…
The semileptonic decays $\tau^- \to \mu^- M (M=\pi^0,\eta,\eta')$ could be sensitive probe for new physics scenarios with lepton flavor violation(LFV). Motivated by the recent Belle measurement, we investigate these decays in type III…
In this paper we study lepton flavor violating semileptonic decays of heavy baryons in a framework of a model with large extra dimensions and a single generation . Resulting branching ratios for these decays mediated by Kaluza-Klein modes…
Lepton flavour non-conserving processes are examined in the context of unified models with U(1)-family symmetries which reproduce successfully the low-energy hierarchy of the fermion mass spectrum and the Kobayashi - Maskawa mixing. These…
The small neutrino mass observed in neutrino oscillations is nicely explained by the seesaw mechanism. Rich phenomenology is generally expected if the heavy neutrinos are not much heavier than the electroweak scale. A model with this…
Among the different scenarios of New Physics, those with an extended Higgs sector are examined with a lot of attention. Recent experimental observations of several anomalies in flavour physics with respect to expectations of the Standard…
Standard Model may allow an extended gauge sector with anomaly-free flavored gauge symmetries, such as $L_{i} - L_{j}$, $B_{i} - L_{j}$, and $B - 3L_{i}$, where $i,j=1,2,3$ are flavor indices. We investigate phenomenological implications of…
Recent anomalies in $B$-meson decays, such as deviations in $R_{D^{(*)}}$ and $B\to K\nu{\bar\nu}$, suggest possible lepton flavor universality violation and new exotic interactions. In this work, we explore these anomalies within a…
We investigate the phenomenology of singlet scalar dark matter in a simple $\rm U(1)_{B-L}$ gauge extension of standard model, made anomaly free with four exotic fermions. The enriched scalar sector and the new gauge boson $Z^\prime$,…
The recent deviations of the experimental data on some parameters of the tree-level semileptonic $B$ and $B_c$ mesons decays from the standard model (SM) predictions indicate considerable violations of the lepton flavor universality, and as…
Heavy quarkonium decays can be used to search for New Physics beyond the Standard Model. In particular, a light Higgs boson could induce a slight (but observable) lepton universality breaking in Upsilon decays. In fact, current experimental…
We derive constraints on the couplings of light vector particles to all first-generation Standard Model fermions using leptonic decays of the charged pion, $\pi^+\to e^+ \nu_e X_\mu$. In models where the net charge to which $X_\mu$ couples…
We investigate the potential of leptonic meson decays $M \to \ell \bar\nu_\ell$, where $M$ is a pseudo-scalar meson, as a probe of neutrino portal dark matter. The model of our focus features a neutral fermion $\psi$ and scalar $\phi$,…
We investigate how the baryon asymmetry of our universe via leptogenesis can be achieved within the framework of the seesaw model with Fritzsch type lepton mass matrices proposed by Fukugita $et. al$. We study the cases with CP-violating…
We investigate the implications of scalar and tensor operators proposed to accommodate the hints of lepton flavor universality violation in charged-current $B$-meson decays. We show that these scenarios unavoidably induce chirality enhanced…
There are indications of a possible breakdown of the standard model, suggesting that $\tau$ lepton interactions violate flavor universality. BABAR, Belle and LHCb report high ratios of $B\to D^{(*)}\tau\nu$. There are long-standing excesses…
The Higgs boson decay into a pair of real or virtual W bosons, with one of them decaying leptonically, is predicted within the Standard Model to have the largest branching fraction of all Higgs decays that involve an isolated electron or…
The observed flavor structure of the standard model arises naturally in "split fermion" models which localize fermions at different places in an extra dimension. It has, until now, been assumed that the bulk masses for such fermions can be…
We discuss in detail the constraints on partial compositeness coming from flavour and CP violation in the leptonic sector. In a first part we present a formulation of partial compositeness in terms of a flavour symmetry group and a set of…